Tobacco powder supported catalyst particles

ABSTRACT

Cut filler compositions, cigarettes, methods for making cut filler compositions and cigarettes, and methods for treating mainstream tobacco smoke of cigarettes are provided that use catalyst particles capable of converting carbon monoxide to carbon dioxide. The catalyst particles are supported on tobacco powder. The tobacco powder supported catalyst particles can be prepared by dry admixing the catalyst particles and tobacco powder or by combining a dispersion of catalyst particles with the tobacco powder.

BACKGROUND

This application claims priority under 35 U.S.C. 119 to U.S. ProvisionalApplication No. 60/649,568, entitled Tobacco Powder Supported CatalystParticles, filed on Feb. 4, 2005, the entire content of which is herebyincorporated by reference.

In the description that follows reference is made to certain structuresand methods, however, such references should not necessarily beconstrued as an admission that these structures and methods qualify asprior art under the applicable statutory provisions. Applicants reservethe right to demonstrate that any of the referenced subject matter doesnot constitute prior art.

Smoking articles, such as cigarettes or cigars, produce both mainstreamsmoke during a puff and sidestream smoke. One constituent of bothmainstream smoke and sidestream smoke is carbon monoxide (CO). Thereduction of carbon monoxide in smoke is desirable.

Despite the developments to date, there remains an interest in improvedand more efficient methods and compositions for reducing the amount ofcarbon monoxide in the mainstream smoke of a smoking article duringsmoking.

SUMMARY

Tobacco cut filler compositions, cigarettes and methods for makingcigarettes incorporating tobacco powder supported catalyst particles aredescribed herein.

One embodiment provides a cut filler composition comprising tobacco andan admixture comprising catalyst particles and tobacco powder particles,wherein the catalyst particles are supported on the tobacco powderparticles.

Another embodiment provides a cigarette comprising tobacco cut fillerand cigarette paper, wherein at least one of the tobacco cut filler andcigarette paper includes an admixture comprising catalyst particlessupported on tobacco powder particles.

A further embodiment provides a method of making a cigarette, comprisingcombining catalyst particles with tobacco powder particles to form anadmixture comprising catalyst particles supported on the tobacco powderparticles; incorporating the admixture on and/or in at least one oftobacco cut filler and cigarette paper; providing the cut filler to acigarette making machine to form a tobacco column; and placing the paperaround the tobacco column to form a tobacco rod of a cigarette.

In another embodiment, the catalyst particles comprise one or moremetallic elements selected from the group consisting of Group IB, IIB,IIIB, IVB, VB, VIB, VIIB, VIII, IIIA and IVA elements of the PeriodicTable of Elements. For example, the catalyst particles can comprisemetal oxides selected from the group consisting of copper manganesespinel, manganese oxide, iron oxide, copper oxide, cerium oxide andmixtures thereof.

The catalyst particles can have a specific surface area of from about 10to 2500 m²/g and an average particle size of less than about 5 μm, orless than about 1 μm. The tobacco powder particles can have an averageparticle size of less than or equal to about 500 microns. The admixture,which comprises catalyst particles supported on tobacco powderparticles, preferably comprises a dry admixture. According to anembodiment, the catalyst particles and the tobacco powder particles canbe combined in the absence of a liquid. According to a furtherembodiment, an admixture comprising catalyst particles supported ontobacco powder particles can be incorporated on and/or in tobacco cutfiller and/or cigarette paper in the absence of a liquid. Preferably,the catalyst particles substantially cover the surface of the tobaccopowder particles. The admixture can comprise from about 0.1 to 50 wt. %,preferably from about 10 to 30 wt. % catalyst particles supported ontobacco powder particles.

The tobacco powder supported catalyst particles can be added to acigarette in an amount effective to convert at least 10% of the carbonmonoxide in the mainstream smoke to carbon dioxide. For example, up toabout 200 mg of the catalyst particles can be added to each cigarette.The admixture can be combined with the tobacco cut filler and/orcigarette paper by dusting the admixture onto the tobacco cut fillerand/or cigarette paper.

According to a further embodiment, the admixture can be formed bycombining catalyst particles with a liquid to form a dispersion;combining the dispersion with the tobacco powder particles; and dryingthe tobacco powder particles to remove the liquid and deposit thecatalyst particles on and/or incorporate the catalyst particle in thetobacco powder particles.

To form a dispersion, catalyst particles can be combined with a liquidselected from the group consisting of distilled water, ethyl alcohol,methyl alcohol, chloroform, aldehydes, ketones, aromatic hydrocarbons,hexanes and mixtures thereof. According to a preferred embodiment, thedispersion can be sprayed onto the tobacco powder particles.

Yet another embodiment provides a method of treating mainstream smoke ofthe cigarette described above, comprising lighting the cigarette to formsmoke and drawing the smoke through the cigarette, wherein the catalystparticles act as a catalyst and/or oxidant for the conversion of carbonmonoxide to carbon dioxide.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 shows an SEM micrograph of black pigment catalyst particles.

FIG. 2 shows CO and CO₂ gas concentrations emitted from a tobacco powdersupported catalyst sample during oxidative pyrolysis.

FIG. 3 shows CO and CO₂ gas concentrations emitted from a tobacco powdersample during oxidative pyrolysis.

FIG. 4 shows the furnace temperature and sample temperature during theoxidative pyrolysis of a tobacco powder supported catalyst sample and atobacco powder sample.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Tobacco cut filler compositions, cigarettes, methods for makingcigarettes and methods for treating mainstream smoke of cigarettesincorporating tobacco powder supported catalyst particles are describedherein. The supported catalyst particles, which can be incorporated in acomponent of a cigarette such as tobacco cut filler and/or cigarettepaper of a cigarette, can act as a catalyst and/or oxidant for theconversion of carbon monoxide (CO) to carbon dioxide (CO₂). Byincorporating the tobacco powder supported catalyst particles into acomponent of a cigarette, the amount of carbon monoxide in mainstreamsmoke can be reduced.

A catalyst is capable of affecting the rate of a chemical reaction,e.g., increasing the rate of oxidation of carbon monoxide to carbondioxide. An oxidant is capable of oxidizing a reactant, e.g., bydonating oxygen to the reactant, such that the oxidant itself isreduced.

“Smoking” of a cigarette means the heating or combustion of thecigarette to form smoke, which can be drawn through the cigarette.Generally, smoking of a cigarette involves lighting one end of thecigarette and, while the tobacco contained therein undergoes acombustion reaction, drawing the cigarette smoke through the mouth endof the cigarette. The cigarette may also be smoked by other means. Forexample, the cigarette may be smoked by heating the cigarette and/orheating using electrical heater means, as described in commonly-assignedU.S. Pat. Nos. 6,053,176; 5,934,289; 5,591,368 and 5,322,075.

The term “mainstream” smoke refers to the mixture of gases passing downthe tobacco rod and issuing through the filter end, i.e., the amount ofsmoke issuing or drawn from the mouth end of a cigarette during smokingof the cigarette.

In addition to the constituents in the tobacco, the temperature and theoxygen concentration within the cigarette during smoking are factorsaffecting the formation and reaction of carbon monoxide and carbondioxide. For example, the total amount of carbon monoxide formed duringsmoking comes from a combination of three main sources: thermaldecomposition (about 30%), combustion (about 36%) and reduction ofcarbon dioxide with carbonized tobacco (at least 23%). Formation ofcarbon monoxide from thermal decomposition, which is largely controlledby chemical kinetics, starts at a temperature of about 180EC andfinishes at about 1050EC. Formation of carbon monoxide and carbondioxide during combustion is controlled largely by the diffusion ofoxygen to the surface (k_(a)) and via a surface reaction (k_(b)). At250EC, k_(a) and k_(b), are about the same. At 400EC, the reactionbecomes diffusion controlled. Finally, the reduction of carbon dioxidewith carbonized tobacco or charcoal occurs at temperatures around 390ECand above.

During smoking there are three distinct regions in a cigarette: thecombustion zone, the pyrolysis/distillation zone, and thecondensation/filtration zone. While not wishing to be bound by theory,it is believed that the catalyst can target the various reactions thatoccur in different regions of the cigarette during smoking.

First, the combustion zone is the burning zone of the cigarette producedduring smoking of the cigarette, usually at the lighted end of thecigarette. The temperature in the combustion zone ranges from about700EC to about 950EC, and the heating rate can be as high as500EC/second. Because oxygen is being consumed in the combustion oftobacco to produce carbon monoxide, carbon dioxide, nitric oxide, watervapor, and various organic compounds, the concentration of oxygen is lowin the combustion zone. The low oxygen concentration coupled with thehigh temperature leads to the reduction of carbon dioxide to carbonmonoxide by the carbonized tobacco. In this region, the tobacco powdersupported catalyst particles can convert carbon monoxide to carbondioxide via both catalysis and oxidation mechanisms. The combustion zoneis highly exothermic and the heat generated is carried to thepyrolysis/distillation zone.

The pyrolysis zone is the region behind the combustion zone, where thetemperatures range from about 200EC to about 600EC. The pyrolysis zoneis where most of the carbon monoxide is produced. The major reaction isthe pyrolysis (i.e. the thermal degradation) of the tobacco thatproduces carbon monoxide, carbon dioxide, nitric oxide, smokecomponents, and charcoal using the heat generated in the combustionzone. There is some oxygen present in this region, and thus the tobaccopowder supported catalyst particles may act as a catalyst for theoxidation of carbon monoxide to carbon dioxide. The catalytic reactionbegins at 150EC and reaches maximum activity around 300EC.

In the condensation/filtration zone the temperature ranges from ambientto about 150EC. The major process in this zone is thecondensation/filtration of the smoke components. Some amount of carbonmonoxide and carbon dioxide diffuse out of the cigarette and some oxygendiffuses into the cigarette. The partial pressure of oxygen in thecondensation/filtration zone does not generally recover to theatmospheric level.

The catalyst particles are supported in and/or on tobacco powderparticles. The catalyst particles can comprise metallic elementsselected from the group consisting of Group IB-VIIB, VIII, IIIA and IVAelements of the Periodic Table of Elements, and mixtures thereof, e.g.,B, C, Mg, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Y, Zr, Nb, Mo,Ru, Rh, Pd, Ag, Sn, Ce, Hf, Ta, W, Re, Os, Ir, Pt and Au. The catalystparticles can be in the form of metal or mixed metal oxides, hydroxies,or mixtures thereof. The tobacco powder supported catalyst particlescomprise an admixture that can be combined with tobacco cut fillerand/or cigarette paper. Preferably, a substantially dry admixture isadded to the tobacco cut filler and/or cigarette paper.

Catalyst particles can be used with a particle size of up to 5 microns.The catalyst particles can have an average particle size less than about1 μm, preferably less than about 300 nm, most preferably less than about50 nm. Catalyst particles have very high surface area to volume ratios,which makes them attractive for catalytic applications. Additionally,smaller catalyst particles can be more easily supported on tobaccopowder particles and can cover more of the surface of a tobacco powderparticle because of its size.

By dispersing catalyst particles on tobacco powder particles, thecatalyst particles are easier to handle and easier to combine withtobacco cut filler and/or cigarette paper than unsupported catalystparticles. This is especially true for smaller catalyst particles,wherein the tobacco powder particles size, friability, etc. can aid inthe handling of the catalyst particles.

Catalyst particles can be combined with tobacco powder particles andtobacco cut filler before and/or during incorporation of the tobacco cutfiller into a cigarette. The tobacco powder particles can act as aseparator, and can inhibit agglomeration or sintering together of thecatalyst particles during packing of the cigarette with the catalystparticles and cut filler and/or during combustion of the cut filler.

It is noted that particle sintering may disadvantageously elongate thecombustion zone, which can result in excess carbon monoxide production.Thus, because the tobacco powder particles separate catalyst particles,the tobacco particles reduce catalyst particle sintering, and thus canreduce elongation of the combustion zone and a loss of active surfacearea of the catalyst particles.

Catalyst particles may be incorporated onto the tobacco powder particlesby various techniques, such as physical admixture, liquid solubilizingmixture, etc. One exemplary physical admixture method includes directlycombining dry catalyst particles with dry tobacco powder particles toform an admixture comprising an intimate mixture of catalyst particlessupported on tobacco powder particles. By this physical admixture,physical surface adhesion and/or agglomeration of the smaller catalystparticles onto the tobacco powder particles can allow the catalystparticles to substantially cover the tobacco powder particles.

According to another embodiment, catalyst particles can be mixed withtobacco particles using liquid. For example, the catalyst particles canfirst be dispersed in a liquid, and then the tobacco powder particlescan be mixed into the catalyst particle containing liquid.Alternatively, the tobacco powder particles may be sprayed or immersedwith a liquid having the dispersed catalyst particles therein and canthen be dried to form an intimate admixture of catalyst particlessupported on the tobacco powder particles. The liquid can besubstantially removed from the tobacco powder particles and the catalystparticles, wherein after substantially removing the liquid, the catalystparticles can remain on the tobacco powder particles such that thecatalyst particles and the tobacco powder particles can be incorporatedinto tobacco cut filler or another portion of a cigarette. The liquidcan be substantially removed, for example, by heating the tobacco powderparticles at a temperature higher than the boiling point of the liquidor by reducing the pressure of the atmosphere surrounding the tobaccopowder particles.

Exemplary liquids that can be used to form a dispersion of the catalystparticles can include, but is not limited to, distilled water, hexanes,aromatic hydrocarbons, methyl alcohol, ethyl alcohol, butyl alcohol,aldehydes, ketones, chloroform, mineral spirits, and mixtures thereof.

Preferably, the catalyst particles at least partially cover the surfaceof the tobacco powder particles to form an admixture. The admixture cancomprise from about 0.1 to 50 wt. % catalyst particles, or from about 10to 30 wt. % catalyst particles, supported on tobacco powder particles.By adjusting the loading of the catalyst particles on the tobacco powderparticles, the activities of the catalyst/oxidant can be regulated.

Catalyst metal oxide powders are commercially available. For instance,MACH I, Inc. (King of Prussia, Pa.) markets iron oxide catalystparticles under the trade names NANOCAT7 Superfine Iron Oxide (SF10) andNANOCAT7 Magnetic Iron Oxide. The NANOCAT7 Superfine Iron Oxide (SF10)is an amorphous ferric oxide in the form of a free flowing powder, witha particle size of about 3 nm, a specific surface area of about 250m²/g, and a bulk density of about 0.05 g/ml. The NANOCAT7 Superfine IronOxide (SF10) is synthesized by a vapor-phase process, which renders itfree of impurities that may be present in conventional catalysts, and issuitable for use in food, drugs, and cosmetics. The NANOCAT7 MagneticIron Oxide is a free flowing powder with a particle size of about 25 nmand a specific surface area of about 40 m²/g. The Shepherd Color Company(Cincinnati, Ohio) markets catalyst oxide powders such as Black 444,which is a black pigment containing a mixture of copper manganese spineland iron and manganese oxides. Based on elemental analysis, the Black444 pigment includes 17.7 wt. % iron, 44.7 wt. % manganese and 37.6 wt.% copper. The Black 444 pigment includes individual and agglomeratedparticles in the size range of about 30 to 300 nm and has a specificsurface area of about 20 m²/g. A scanning electron microscope (SEM)micrograph of Black 444 pigment powder is shown in FIG. 1.

The tobacco powder particles can be produced by comminuting maturedtobacco leaves, but can also be reclaimed from waste produced byconventional tobacco processing. The tobacco from which the tobaccopowder particles are produced can be un-cured or cured. For example,tobacco powder particles can be prepared by grinding and sievingflue-cured Bright tobacco.

The tobacco powder particles can be sized as desired. For example,tobacco laminae and stem can be finely divided to preferred sizes.Preferably, the tobacco powder particles used as catalyst support havean average particle size of 1 to 1000 microns. In exemplary embodiments,tobacco powder particles have an average particle size of less than 500microns (e.g., if larger catalysts are desired), less than 100 micronsor less than 40 microns, though larger particles can be used.

The relative amounts of catalyst particles and tobacco powder particlesin the admixture can vary. In general, catalyst particles and tobaccopowder particles can be combined in any suitable ratio to give a desiredloading of catalyst particles on the tobacco powder. For example, ratiosof catalyst particles to tobacco powder can range from about 0.1 percentto about 50 percent, preferably about 10 percent to about 30 percent, ona dry weight basis. The tobacco powder particle can maintain itsoriginal volume after the catalyst particles are provided in intimatecontact therewith and can be provided in an essentially dry form priorto the provision of catalyst particles. For example, catalyst iron oxideparticles or copper oxide particles can be combined with tobacco powderparticles to produce from about 0.1% to 50% wt. %, e.g., at least 5 wt.%, 10 wt. %, 20 wt. %, 30 wt. % or 40 wt. % catalyst particles of ironoxide or copper oxide supported on the tobacco powder particles.

The amount of catalyst particles added to a cigarette can vary. Forexample, the amount of the admixture (e.g., the mixture of catalystparticles supported on tobacco powder particles) can be at least about5% by weight, if less catalytic activity is desired, or can be higher,at levels between about 10 to 20%, if desired, of the tobacco cut fillerin a cigarette. By way of a non-limiting example, cigarettes cancomprise up to about 200 mg or more of the catalyst particles percigarette or about 250 mg or more of the admixture per cigarette.

By way of example, 250 g of Black 444 is incorporated via dry admixturewith 500 g of flue-cured Bright tobacco ground and sieved to a particlesize of about 40-60 mesh (about 250 to 420 μm). The sample is placed ina programmable quartz tube furnace between pieces of quartz wool. Boththe temperature of the sample and the temperature of the furnace aremonitored via thermocouples. Gas flow into the tube furnace iscontrolled using Hastings digital flow meters. A gas mixture comprising21% O₂ (balance He) is passed over the sample at a flow rate of 1000sccm and the sample is pyrolyzed by heating the furnace at a constantheating rate of 15° C./min. from room temperature to about 800° C. Gasflow out of the furnace is filtered by a fiberglass filter pad and thenfed into an online multichannel gas analyzer available from RosemountAnalytical (Model NGA2000-MLT) that measures the composition of CO, CO₂and O₂ in the effluent gas. For comparison, the concentration of gasesemitted from a 500 mg sample of identically prepared tobacco powder (nocatalyst) is also measured.

Concentration profiles for CO and CO₂ are shown in FIGS. 2 and 3 for thepyrolysis of tobacco powder particles incorporated with Black 444catalyst (FIG. 2), as formed above, and for tobacco powder particlesonly (FIG. 3) for comparison as noted above. The ratio of CO/CO₂ for thesample comprising catalyst particles supported on tobacco powder isabout 0.17 while the ratio of CO/CO₂ for the sample comprising tobaccopowder particles only is about 0.86. Thus, the supported catalystappears to significantly reduce the CO/CO₂ ratio. Additionally, FIG. 4shows the furnace and sample temperatures for each of the test runs. Asshown in FIG. 4, the sample temperatures during each measurement exceedthe programmed furnace temperature. In the case of the tobacco/catalystpyrolysis the sample temperature starts to increase earlier and sustainsa value greater than the programmed furnace temperature longer than fortobacco pyrolysis only. Thus, comparing the tobacco powder particlessample with the tobacco powder particles incorporated with Black 444catalyst, a 56% decrease in the measured output of CO and a 52% increasein the measured output of CO₂ upon pyrolysis can be attained.

It is noted that during the conversion of CO to CO₂, the material of thecatalyst particles can be reduced. For example, catalyst Fe₂O₃ particlescan be reduced to Fe₃O₄, FeO or Fe during the reaction of CO to CO₂.However, by using the tobacco powder particles as support, the tobaccopowder particles can advantageously act as a spacer between the catalystparticles and prevent them from agglomerating together, which wouldresult in a loss of surface area and catalytic activity; and thusreduction can be less of a potential problem. Additionally, bysupporting the catalyst particles on tobacco powder particles theadhesion of the catalyst particles to cut filler and/or cigarette papercan be improved and the possibility of entrainment of the catalystparticles during smoking can be reduced.

While other catalysts can be used, preferred catalyst particles includeiron oxide catalyst particles because iron oxide can have a dualfunction as a CO catalyst in the presence of oxygen, and as a CO oxidantfor direct oxidation of CO in the absence of oxygen. Preferably,exemplary catalysts can also be used as an oxidant, which can beespecially useful for certain applications, such as within a burningcigarette where the oxidation characteristics can be utilized if thepartial pressure of oxygen in the cigarette is low. Catalyst particles,such as iron oxide particles, can also act as a catalyst for theconversion of CO to CO₂ according to the equation 2CO+O₂6 2CO₂. Forexample, catalyst iron oxide particles can act as an oxidant for theconversion of CO to CO₂ according to the equation 3CO+F₂O₃6 3CO₂+2Fe.

As mentioned above, catalyst particles may be capable of acting as bothan oxidant for the conversion of carbon monoxide to carbon dioxide andas a catalyst for the conversion of carbon monoxide to carbon dioxide,wherein such actions can be cigarette location specific. For example,catalyst particles can act as a catalyst in the pyrolysis zone and canact as an oxidant in the combustion zone.

The supported catalyst particles can be distributed throughout or onlyin a portion of the tobacco rod portion of a cigarette. By providingsupported catalyst particles throughout the tobacco rod, it is possibleto reduce the amount of carbon monoxide drawn through the cigarette, andparticularly at both the combustion region and in the pyrolysis zone.Alternatively, by providing supported catalyst particles in only aportion of the tobacco rod, less catalyst can be used as desired.

An admixture of catalyst particles supported on tobacco powder particlescan be provided along the length of a tobacco rod by distributing theadmixture on a pre-formed tobacco rod incorporating the admixture intocut filler tobacco prior to forming a tobacco rod, incorporating theadmixture into cigarette paper, or placing the admixture on surfaces ofcigarette paper. For example, the admixture can be added to a tobaccorod prior to wrapping cigarette paper around a tobacco rod (e.g. mixingor dusting the admixture in or on the tobacco rod) or added to cutfiller tobacco stock supplied to a cigarette making machine. Accordingto an exemplary embodiment, a dry admixture of catalyst particlessupported on tobacco powder particles can be combined directly withtobacco cut filler prior to providing the cut filler to a cigarettemaking machine for form a tobacco column. Alternatively, duringcigarette paper manufacture, the admixture can be added in an amountthat does not inhibit the properties of the cigarette paper (e.g.,burning rate, taste, etc.), or after cigarette paper manufacture, theadmixture can be placed on a surface or a portion of the surface of thecigarette paper (e.g., dusting the admixture on to the paper).

The amount of the admixture can be selected such that the amount ofcarbon monoxide in mainstream smoke is reduced during smoking of acigarette. Preferably, the amount of the admixture will be acatalytically effective amount, e.g., more than 1 mg, for example, about80 to 250 mg/cigarette can lead to significant CO reduction.

One embodiment provides a cut filler composition comprising cut fillerand an admixture of tobacco powder particles and catalyst particles, asdescribed above, wherein the admixture is capable of converting carbonmonoxide to carbon dioxide, upon combustion of the cut fillercomposition.

Any suitable tobacco mixture may be used for the cut filler. Examples ofsuitable types of tobacco materials include flue-cured, Burley, Marylandor Oriental tobaccos, the rare or specialty tobaccos, and blendsthereof. The tobacco material can be provided in the form of tobaccolamina, processed tobacco materials, such as volume expanded or puffedtobacco, processed tobacco stems, such as cut-rolled or cut-puffedstems, reconstituted tobacco materials, or blends thereof. The cutfiller can also include tobacco substitutes if desired.

In cigarette manufacture, tobacco is normally employed in the form ofcut filler, i.e. in the form of shreds or strands cut into widthsranging from about 1/10 inch to about 1/20 inch or even 1/40 inch. Thelengths of the shreds or strands can range from between about 0.25inches to about 3.0 inches. Additionally, cigarettes can also furtherinclude one or more flavorants or other additives (e.g. burn additives,combustion modifying agents, coloring agents, binders, etc.) as desired.

Another embodiment provides a cigarette with tobacco cut filler andcigarette paper, wherein at least one of the tobacco cut filler andcigarette paper includes an admixture comprising catalyst particlessupported on tobacco powder particles.

A further embodiment provides a method of making a cigarette, comprisingcombining catalyst particles with tobacco powder particles to form anadmixture comprising catalyst particles supported on the tobacco powderparticles; incorporating the admixture on and/or in at least one oftobacco cut filler and cigarette paper; providing the cut filler to acigarette making machine to form a tobacco column; and placing the paperaround the tobacco column to form a tobacco rod of a cigarette.

Techniques for cigarette manufacture are known in the art. Anyconventional or modified cigarette making technique may be used toincorporate the admixture. The resulting cigarettes can be manufacturedto any known specifications using standard or modified cigarette makingtechniques and equipment. Typically, the cut filler composition isoptionally combined with other cigarette additives, and provided to acigarette making machine to produce a tobacco rod, which is then wrappedin cigarette paper, and optionally tipped with filters.

Cigarettes may range from about 50 mm to about 120 mm in length. Thecircumference is from about 15 mm to about 30 mm in circumference, andpreferably around 25 mm. The tobacco packing density is typicallybetween the range of about 100 mg/cm³ to about 300 mg/cm³, andpreferably 150 mg/cm³ to about 275 mg/cm³.

Yet another embodiment provides a method of treating mainstream tobaccosmoke of the cigarette described above, which involves lighting thecigarette to form smoke and drawing the smoke through the cigarette,wherein the supported catalyst particles act as a catalyst and/oroxidant for the conversion of carbon monoxide to carbon dioxide.

While preferred embodiments have been described, it is to be understoodthat variations and modifications may be resorted to as will be apparentto those skilled in the art. Such variations and modifications are to beconsidered within the purview and scope of the claims as appendedhereto.

1-3. (canceled)
 4. The method of claim 12, wherein the admixturecomprises: a dry admixture; and/or from about 0.1 to 50 wt. % or fromabout 10 to 30 wt. % catalyst particles supported on tobacco powderparticles.
 5. (canceled) 6-7. (canceled)
 8. The method of claim 12,wherein the catalyst particles: have an average particle size of lessthan about 5 μm or less than about 50 nm.
 9. The method of claim 12,wherein both the catalyst particles and tobacco powder particles in thecigarette are each substantially moisture-free; and/or wherein thecatalyst particles at least partially cover the surfaces of the tobaccopowder particles; and/or wherein the admixture of catalyst particles andtobacco powder particles comprises up to about 25% by weight of thetobacco cut filler; and/or wherein the admixture of catalyst particlesand tobacco powder are present in the cigarette in an amount effectiveto convert at least 10% of the carbon monoxide in mainstream smoke tocarbon dioxide; and/or wherein the admixture comprises from about 0.1 to50 wt. % or from about 10 to 30 wt. % catalyst particles supported ontobacco powder particles.
 10. The method of claim 12, wherein thetobacco powder particles have an average particle size of less than 500microns, less than 100 microns, or less than 40 microns.
 11. The methodof claim 12, wherein the cigarette comprises: up to about 200 mg of thecatalyst particles per cigarette; and/or up to about 250 mg of theadmixture per cigarette.
 12. A method of making a cigarette, comprising:(i) combining catalyst particles with tobacco powder particles to forman admixture comprising catalyst particles supported on the tobaccopowder particles; (ii) incorporating the admixture on and/or in at leastone of tobacco cut filler and cigarette paper; (iii) providing the cutfiller to a cigarette making machine to form a tobacco column; and (iv)placing the paper around the tobacco column to form a tobacco rod of acigarette.
 13. The method of claim 12, comprising combining catalystparticles comprising one or more metallic elements selected from thegroup consisting of Group IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIII, IIIAand IVA elements of the Periodic Table of Elements with tobacco powderparticles to form the admixture.
 14. The method of claim 12, comprising:combining catalyst particles comprising copper manganese spinel,manganese oxide, iron oxide, copper oxide, cerium oxide and mixturesthereof with tobacco powder particles to form the admixture; and/orcombining the catalyst particles and the tobacco powder particles in theabsence of a liquid to form the admixture; and/or combining catalystparticles having an average diameter of less than about 5 microns withthe tobacco powder particles to form the admixture; and/or combining thecatalyst particles with tobacco powder particles having an averagediameter of less than 500 microns, less than 100 microns, or less than40 microns to form the admixture; and/or combining the catalystparticles with the tobacco powder particles in an amount to at leastpartially cover the surface of the tobacco powder particles with thecatalyst particles to form the admixture.
 15. The method of claim 12,wherein incorporating the admixture on and/or in at least one of tobaccocut filler and cigarette paper; comprises: incorporating the admixtureon and/or in at least one of the tobacco cut filler and cigarette paperin the absence of a liquid; and/or incorporating the admixture on and/orin at least one of the tobacco cut filler and cigarette paper by dustingthe admixture onto at least one of the tobacco cut filler and cigarettepaper.
 16. The method of claim 12, wherein incorporating the admixtureon and/or in at least one of tobacco cut filler and cigarette paper;comprises: incorporating an admixture having from about 0.1 to 50 wt. %or from about 10 to 30 wt. % catalyst particles supported on tobaccopowder particles on and/or in at least one of the tobacco cut filter andcigarette paper; and/or incorporating the admixture on and/or in tobaccocut filler in an amount effective to convert at least 10% of the carbonmonoxide in the mainstream smoke to carbon dioxide; and/or incorporatingthe admixture on and/or in cigarette paper in an amount effective toconvert at least 10% of the carbon monoxide in the mainstream smoke tocarbon dioxide.
 17. The method of claim 12, further comprising formingthe admixture by: combining catalyst particles with a liquid to form adispersion; combining the dispersion with the tobacco powder particles;and drying the tobacco powder particles to a remove the liquid anddeposit the catalyst particles on and/or in the tobacco powder particlesto form the admixture.
 18. The method of claim 17, wherein the combiningcatalyst particles with a liquid to form a dispersion comprises:combining catalyst particles comprising copper manganese spinel,manganese oxide, iron oxide, copper oxide and/or cerium oxide with theliquid to form the dispersion; and/or combining the catalyst particleswith a liquid selected from the group consisting of water, ethylalcohol, methyl alcohol, chloroform, aldehydes, ketones, aromatichydrocarbons, hexanes and mixtures thereof to form a dispersion.
 19. Themethod of claim 17, wherein the dispersion is sprayed onto the tobaccopowder particles.
 20. A method of treating mainstream tobacco smoke ofthe cigarette made by the method of claim 12, comprising lighting thecigarette to form smoke and drawing the smoke through the cigarette,wherein the catalyst particles act as a catalyst and/or oxidant for theconversion of carbon monoxide to carbon dioxide.